Question

0 ft. Impeller Diameter (D) = 3.0 ft. Impeller type = Flat blade turbine. # of blades = 6 Blade width (W) =7 inches. Blade length (L) = 9 inches. Number of Baffles = 4; equally spaced. Baffle width (B) = 11 inches. Liquid Depth (H) = 9.0 feet. Impeller height above vessel bottom (Z) = 3 feet.

(a) 2, 400 rph

(b) 4, 500 rph

(c) 3, 500 rph

(d) 3, 600 rph

This question was posed to me by my school principal while I was bunking the class.

The above asked question is from Power Requirements for Mixing in division Fluid Flow and Mixing of Bioprocess Engineering

Answer 1

Right choice is (d) 3, 600 rph

For explanation: N = revolutions per hour (rph). The agitation speed is given in the example as 60 revolutions per minute, which when multiplied by 60 minutes/hr yields:

N = 60 rpm * 60 = 3,600 rph.